An aircraft liquid hydrogen power system

Abstract

The application belongs to the technical field of hydrogen energy application, and particularly relates to a liquid hydrogen power system for an airplane. The system comprises a liquid hydrogen storage tank, a liquid hydrogen pump, a heat exchanger I, a heat exchanger II, a hydrogen engine I, a hydrogen engine II, a plurality of stop valves, a safety valve and a pressure reducing valve; the heat exchange capacity of the heat exchanger I is higher than that of the heat exchanger II; the system adopts the liquid hydrogen pump as a liquid hydrogen conveying driving device, adopts heat exchangers with different heat exchange capacities as liquid hydrogen heat exchange devices, and only adopts liquid hydrogen stop valves as system control valves; the hydrogen fuel flow demand under different working conditions in the operation process of the liquid hydrogen airplane is fully considered, a simple hydrogen conveying process is proposed, and through the cooperation mechanism of the liquid hydrogen pump, the heat exchanger and the stop valve, the hydrogen fuel conveying flow is finally rapidly adjusted to match the flow demand under different working conditions, the stable and continuous supply of the hydrogen fuel and the rapid adjustment of the conveying flow are finally realized, the system reliability is ensured, the control process is simplified, and the overall thermal efficiency of the system is improved.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen energy application technology, specifically relating to an aircraft liquid hydrogen propulsion system. Background Technology

[0002] With the increasing research on hydrogen-powered aircraft by various countries, their propulsion systems have received widespread attention. In the actual operation of hydrogen-powered aircraft, repeated adjustments are required under various operating conditions, including taxiing, takeoff and climb, cruise, approach and landing, go-around, and taxiing in. The operating state of the aircraft's power equipment differs under these different conditions, resulting in varying hydrogen fuel flow requirements. Therefore, the ability to rapidly adjust the hydrogen fuel delivery flow under different operating conditions is a necessary condition for the stable operation of hydrogen-powered aircraft propulsion systems.

[0003] Traditional aircraft use aviation gasoline as fuel, with multiple fuel tanks, including main and auxiliary fuel tanks, in the fuselage. They employ an alternating fuel supply system and are equipped with multiple booster pumps, allowing any fuel tank to supply fuel to any engine. In the event of a booster pump failure, the engine can still drive the fuel pump to ensure fuel supply. Therefore, stable fuel supply and flow control can be achieved through the coordinated adjustment of pumps and valves. However, the onboard liquid hydrogen storage system of hydrogen-powered aircraft is limited by the characteristics of liquid hydrogen, storage methods, insulation requirements, and fuselage size. It often adopts a single large storage tank design, which is not conducive to a continuous and stable supply of onboard fuel. As a cryogenic fluid, liquid hydrogen has a low vaporization temperature and low latent heat of vaporization, which poses challenges to the structural, insulation, and sealing design of complex regulating mechanisms such as liquid hydrogen regulating valves. At the same time, the complex transportation process may cause heat leakage, leading to liquid hydrogen vaporization and subsequent vapor lock, which can hinder fuel delivery.

[0004] Existing technologies mainly focus on the liquid hydrogen fuel transportation process, using regulating valves and other equipment to achieve stepless regulation of the liquid hydrogen fuel's flow rate, temperature, and other physical properties. However, they do not consider the specific needs of hydrogen-powered aircraft for hydrogen fuel flow rate under different operating conditions, making the regulation process complex. Furthermore, regulating valves and other equipment used with cryogenic working fluids have a high risk of damage and failure, resulting in poor reliability and making them unsuitable for applications in high-altitude environments with high reliability requirements, such as aircraft. Summary of the Invention

[0005] In view of this, the present invention provides an aircraft liquid hydrogen propulsion system, which, through the cooperation mechanism of liquid hydrogen pump, heat exchanger and shut-off valve, ultimately achieves a stable and continuous supply of hydrogen fuel and rapid adjustment of the delivery flow rate to match the flow requirements under different operating conditions.

[0006] This invention is achieved through the following technical solution:

[0007] An aircraft liquid hydrogen propulsion system includes a liquid hydrogen storage tank, a liquid hydrogen pump, heat exchanger I, heat exchanger II, hydrogen engine I, and hydrogen engine II, wherein the heat exchanger I has a higher heat exchange capacity than the heat exchanger II.

[0008] The outlet of the liquid hydrogen storage tank is connected to the inlet of the liquid hydrogen pump via a pipeline. The pipeline at the outlet of the liquid hydrogen pump is divided into two branches. The first branch C is connected to the inlet of heat exchanger I and is equipped with a shut-off valve III. The second branch D is connected to the inlet of heat exchanger II and is equipped with a shut-off valve IV. A shut-off valve I is installed on the pipeline at the outlet of the liquid hydrogen pump.

[0009] The outlet pipeline of heat exchanger I is divided into a first branch E and a second branch F. The first branch E is connected to the input end of hydrogen engine I and hydrogen engine II connected in parallel, and a shut-off valve VI is installed on the first branch E. The second branch F is connected to the inlet of heat exchanger II, and a shut-off valve V is installed on the second branch F. The outlet of heat exchanger II is connected to the first branch E through a pipeline. A pressure reducing valve I is installed on the pipeline at the inlet of hydrogen engine I, and a pressure reducing valve II is installed on the pipeline at the inlet of hydrogen engine II.

[0010] Furthermore, the liquid hydrogen storage tank is equipped with a storage tank safety valve, the inlet pipeline of hydrogen engine I is equipped with pipeline safety valve I, and the inlet pipeline of hydrogen engine II is equipped with pipeline safety valve II.

[0011] Furthermore, the liquid hydrogen power system also includes a standby liquid hydrogen pump II; the standby liquid hydrogen pump II and the main liquid hydrogen pump I are connected in parallel; and a shut-off valve II is provided on the outlet pipeline of the standby liquid hydrogen pump II.

[0012] Furthermore, the hydrogen engine I and hydrogen engine II are internal combustion engine hydrogen engines or fuel cell hydrogen engines.

[0013] Furthermore, the liquid hydrogen storage tank has a spherical, cylindrical, or irregular shape.

[0014] Furthermore, the shut-off valves I, II, III, IV, V, VI, the tank safety valve, I, II, and II, as well as the pressure reducing valves I and II, are all electrically connected to an external control system.

[0015] Beneficial effects:

[0016] (1) The present invention provides an aircraft liquid hydrogen power system. The system achieves a stable and continuous supply of hydrogen fuel and rapid adjustment of the delivery flow rate through the cooperation mechanism of liquid hydrogen pump, heat exchanger and shut-off valve, so as to match the flow rate and heat exchange requirements of the aircraft under different operating conditions. The system enables liquid hydrogen fuel regulation to be carried out by liquid hydrogen shut-off valve, which ensures system reliability, simplifies the regulation process and improves the overall thermal efficiency of the system.

[0017] (2) The present invention provides an aircraft liquid hydrogen power system, wherein the system is equipped with a storage tank safety valve and a pipeline safety valve. In the event of an emergency such as overpressure of the liquid hydrogen storage tank or overpressure of the hydrogen supply pipeline during the operation of the power system, the hydrogen fuel in the storage tank and pipeline can be emptied in an emergency through the safety valve to maintain the safe operation of the system.

[0018] (3) The present invention provides an aircraft liquid hydrogen power system, wherein the system is equipped with a main liquid hydrogen pump I and a backup liquid hydrogen pump II, wherein the backup liquid hydrogen pump II is connected in parallel with the main liquid hydrogen pump I; when the main liquid hydrogen pump I fails or is damaged, the backup liquid hydrogen pump II is started to pump liquid hydrogen fuel from the liquid hydrogen storage tank to ensure that the system can operate continuously and stably.

[0019] (4) The present invention provides an aircraft liquid hydrogen power system, wherein the shut-off valve and the pressure reducing valve in the system are electrically connected to an external control system to realize remote automatic control of the system and improve the system operating efficiency and safety. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the liquid hydrogen propulsion system for aircraft described in this invention;

[0021] Among them, 1-Storage tank safety valve, 2-Liquid hydrogen storage tank, 3-Main liquid hydrogen pump I, 4-Standby liquid hydrogen pump II, 5-Stop valve I, 6-Stop valve II, 7-Stop valve III, 8-Stop valve IV, 9-Heat exchanger I, 10-Heat exchanger II, 11-Stop valve V, 12-Stop valve VI, 13-Pipeline safety valve I, 14-Pipeline safety valve II, 15-Pressure reducing valve I, 16-Pressure reducing valve II, 17-Hydrogen engine I, 18-Hydrogen engine II, 19-Pipeline A, 20-First branch C, 21-Second branch D, 22-First branch E, 23-Second branch F. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] An aircraft liquid hydrogen propulsion system as described in this embodiment, such as Figure 1 As shown, it includes a liquid hydrogen storage tank 2, a main liquid hydrogen pump I 3, a standby liquid hydrogen pump II 4, a heat exchanger I 9, a heat exchanger II 10, a hydrogen engine I 17, a hydrogen engine II 18, several shut-off valves, several safety valves, and several pressure reducing valves.

[0024] The heat sources of heat exchangers I9 and II10 are the heat generated by the engine operation or the heat generated by using electric power to drive an electric heater (not shown in the figure). The heat exchange capacity of heat exchanger I9 is ​​higher than that of heat exchanger II10. The hydrogen engine I17 and hydrogen engine II18 are internal combustion engine hydrogen engines or fuel cell hydrogen engines. The shut-off valve, safety valve and pressure reducing valve are all electrically connected to the external control system, and the opening and closing of the shut-off valve, safety valve and pressure reducing valve are automatically controlled by the external control system.

[0025] The shut-off valves are as follows: shut-off valve I5, shut-off valve II6, shut-off valve III7, shut-off valve IV8, shut-off valve V11 and shut-off valve VI12;

[0026] The pressure reducing valves are: pressure reducing valve I15 and pressure reducing valve II16;

[0027] The safety valves are as follows: tank safety valve 1, pipeline safety valve I 13, and pipeline safety valve II 14;

[0028] The liquid hydrogen storage tank 2 is cylindrical. The outlet of the liquid hydrogen storage tank 2 is connected to the inlet of the liquid hydrogen pump I3 through a pipeline. The inlet and outlet of the liquid hydrogen pump I3 are provided with pipelines, and the outlet pipeline is provided with a shut-off valve I5. The inlet and outlet of the standby liquid hydrogen pump II4 are provided with pipelines, and the outlet pipeline is provided with a shut-off valve II6. After the liquid hydrogen pump I3 and the standby liquid hydrogen pump II4 are connected in parallel, the input end is connected to the outlet of the liquid hydrogen storage tank 2, and the output end is connected to the inlet of heat exchanger I9 and heat exchanger II10 through pipeline A19. Specifically, pipeline A19 is divided into two branches. The first branch C20 is connected to the inlet of heat exchanger I9 and is provided with a shut-off valve III7. The second branch D21 is connected to the inlet of heat exchanger II10 and is provided with a shut-off valve IV8.

[0029] The outlet pipeline of heat exchanger I9 is ​​divided into a first branch E22 and a second branch F23. The first branch E22 is connected to the input end of hydrogen engine I17 and hydrogen engine II18 connected in parallel, and a shut-off valve VI12 is installed on the first branch E22. The second branch F23 is connected to the inlet of heat exchanger II10, and a shut-off valve V11 is installed on the second branch F23. The outlet of heat exchanger II10 is connected to the first branch E22. A pressure reducing valve I15 is installed on the pipeline at the inlet of hydrogen engine I17, and a pressure reducing valve II16 is installed on the pipeline at the inlet of hydrogen engine II18.

[0030] The liquid hydrogen storage tank 2 is equipped with a storage tank safety valve 1, and the inlet pipeline of hydrogen engine I 17 is equipped with a pipeline safety valve I 13, while the inlet pipeline of hydrogen engine II 18 is equipped with a pipeline safety valve II 14. During the operation of the power system, in case of an emergency such as overpressure in the liquid hydrogen storage tank 2, the hydrogen fuel in the liquid hydrogen storage tank 2 can be urgently emptied by opening the storage tank safety valve 1; in case of an emergency such as overpressure in the hydrogen supply pipeline, the hydrogen fuel can be urgently emptied by opening the pipeline safety valves I 13 and II 14 to maintain the safe operation of the system.

[0031] The main liquid hydrogen pump I3 can pump liquid hydrogen from the liquid hydrogen storage tank 2 and regulate the output liquid hydrogen flow rate. If the main liquid hydrogen pump I3 fails or is damaged during operation, the shut-off valve I5 is closed, the shut-off valve II6 is opened, and the standby liquid hydrogen pump II4 is started to pump liquid hydrogen fuel from the liquid hydrogen storage tank 2.

[0032] Working principle

[0033] Aircraft have different hydrogen fuel flow requirements under different operating conditions. During the reuse of the liquid hydrogen power system of the aircraft described in Example 1, a stable and continuous supply of hydrogen fuel and rapid adjustment of the delivery flow can be achieved through the cooperation mechanism of liquid hydrogen pump, heat exchanger and shut-off valve to match the flow requirements under different operating conditions.

[0034] (1) During aircraft taxiing in and out, when the demand for hydrogen fuel flow is relatively low: the main liquid hydrogen pump I3 is adjusted to control the output flow of liquid hydrogen fuel pumped from the liquid hydrogen storage tank 2 (when the main liquid hydrogen pump I3 fails, the backup liquid hydrogen pump II4 is adjusted) to match the demand of hydrogen engine I17 and hydrogen engine II18; the external control system closes shut-off valves III7, V11, and VI12, and opens shut-off valve I5 (when using backup liquid hydrogen pump II4, shut-off valve II6 is opened) and shut-off valve IV8, so that the liquid hydrogen fuel flowing out of pipeline A19 can only pass through the second branch D. 21. Hydrogen gas is generated through heat exchanger Ⅱ10, which has a smaller heat exchange capacity, instead of heat exchanger Ⅰ9, which has a larger heat exchange capacity. The hydrogen fuel flows out from the outlet of heat exchanger Ⅱ10, passes through the first branch E22, and is then fed into the parallel hydrogen engines Ⅰ17 and Ⅱ18. Pressure reducing valves Ⅰ15 and Ⅱ16 are installed on the inlet pipes of hydrogen engines Ⅰ17 and Ⅱ18, respectively, to regulate the pressure of the supplied hydrogen fuel.

[0035] (2) Under operating conditions where the demand for hydrogen fuel flow is moderate, such as during aircraft cruise, approach landing, and go-around: the main liquid hydrogen pump I3 is adjusted to control the output flow of liquid hydrogen fuel pumped from the liquid hydrogen storage tank 2 (when the main liquid hydrogen pump I3 fails, the backup liquid hydrogen pump II4 is adjusted) to match the demand of hydrogen engine I17 and hydrogen engine II18; the external control system closes shut-off valves IV8 and V11, and opens shut-off valve I5 (when using backup liquid hydrogen pump II4, shut-off valve II6 is opened), shut-off valve III7, and shut-off valve... VI12 ensures that the liquid hydrogen fuel flowing out of pipeline A19 can only pass through the first branch C20 and the heat exchanger I9 with a larger heat exchange capacity, without passing through heat exchanger II10, and completes heat exchange to generate hydrogen within heat exchanger I9; the hydrogen fuel flows out from the outlet of heat exchanger I9, passes through the first branch E22, and is then fed into the parallel hydrogen engines I17 and II18 respectively; pressure reducing valves I15 and II16 are respectively installed on the inlet pipelines of hydrogen engine I17 and hydrogen engine II18 to regulate the pressure of the supplied hydrogen fuel.

[0036] (3) Under operating conditions with high demand for hydrogen fuel flow, such as during aircraft takeoff and climb: Adjust the main liquid hydrogen pump I3 to control the output flow of liquid hydrogen fuel pumped from liquid hydrogen storage tank 2 (when the main liquid hydrogen pump I3 fails, adjust the backup liquid hydrogen pump II4) to match the demand of hydrogen engine I17 and hydrogen engine II18; the external control system closes shut-off valves IV8 and IV12, and opens shut-off valve I5 (when using backup liquid hydrogen pump II4, open shut-off valve II6), shut-off valve III7, and shut-off valve V11 to allow the flow from pipeline A19. Liquid hydrogen fuel first passes through heat exchanger I9 with a larger heat exchange capacity via the first branch C20, and then through heat exchanger I10 with a smaller heat exchange capacity via the second branch F23. Heat exchange is completed in heat exchangers I9 and I10 to generate hydrogen. The hydrogen fuel flows out from the outlet of heat exchanger II10, and after passing through the first branch E22, it is fed into the parallel hydrogen engines I17 and II18 respectively. Pressure reducing valves I15 and II16 are installed on the inlet pipes of hydrogen engines I17 and II18 respectively to regulate the pressure of the supplied hydrogen fuel.

[0037] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An aircraft liquid hydrogen propulsion system, characterized in that: It includes a liquid hydrogen storage tank, a liquid hydrogen pump, heat exchanger I, heat exchanger II, hydrogen engine I, and hydrogen engine II. The heat exchanger I has a higher heat exchange capacity than heat exchanger II. The outlet of the liquid hydrogen storage tank is connected to the inlet of the liquid hydrogen pump via a pipeline. The pipeline at the outlet of the liquid hydrogen pump is divided into two branches. The first branch C is connected to the inlet of heat exchanger I and is equipped with a shut-off valve III. The second branch D is connected to the inlet of heat exchanger II and is equipped with a shut-off valve IV. A shut-off valve I is installed on the pipeline at the outlet of the liquid hydrogen pump. The outlet pipeline of heat exchanger I is divided into a first branch E and a second branch F. The first branch E is connected to the input end of hydrogen engine I and hydrogen engine II connected in parallel, and a shut-off valve VI is installed on the first branch E. The second branch F is connected to the inlet of heat exchanger II, and a shut-off valve V is installed on the second branch F. The outlet of heat exchanger II is connected to the first branch E through a pipeline. A pressure reducing valve I is installed on the pipeline at the inlet of hydrogen engine I, and a pressure reducing valve II is installed on the pipeline at the inlet of hydrogen engine II.

2. The liquid hydrogen propulsion system for aircraft according to claim 1, characterized in that: The liquid hydrogen storage tank is equipped with a storage tank safety valve, and a pipeline safety valve I is installed on the pipeline at the inlet of hydrogen engine I, while a pipeline safety valve II is installed on the pipeline at the inlet of hydrogen engine II.

3. The liquid hydrogen propulsion system for aircraft according to claim 2, characterized in that: The liquid hydrogen power system also includes a standby liquid hydrogen pump II; the standby liquid hydrogen pump II and the main liquid hydrogen pump I are connected in parallel; a shut-off valve II is installed on the outlet pipeline of the standby liquid hydrogen pump II.

4. An aircraft liquid hydrogen propulsion system according to any one of claims 1-3, characterized in that: The hydrogen engine I and hydrogen engine II are internal combustion engine hydrogen engines or fuel cell hydrogen engines.

5. An aircraft liquid hydrogen propulsion system according to any one of claims 1-3, characterized in that: The liquid hydrogen storage tank is spherical, cylindrical, or irregularly shaped.

6. The liquid hydrogen propulsion system for aircraft according to claim 3, characterized in that: The shut-off valves I, II, III, IV, V, and VI, the tank safety valve, the pipeline safety valve I, the pipeline safety valve II, the pressure reducing valve I, and the pressure reducing valve II are all electrically connected to the external control system.

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